1. Field of the Invention
This invention pertains to transmission devices and systems for racing automobiles, and more particularly to a transmission for use in drag racing wherein quick reaction times at the starting line and maximum acceleration are primary to success. More particularly, the invention is a racing automotive transmission, with an integral anti-lockup assembly, which is compact, lightweight, and configured for quick and easy disassembly and repair. The use of a torque converter with the invention allows a racing vehicle using the invention to be held stationary on the starting line with the engine at maximum torque by utilizing a transmission brake, and then instantly allows the vehicle to accelerate.
2. Background
In automobile racing generally, and drag racing in particular, the use of high horsepower engines and the resulting high drive loads require specialized transmissions. Drag racing transmissions must be able to provide maximum acceleration immediately from the start of a race and continuing throughout the race, under high drive load, and with minimal interruption during gear shifting.
Currently, there are two types of after-market automotive drive systems available that allow the use of a torque converter with a racing planetary gear set. In both cases the drive systems are stand-alone units to which a complete planetary transmission is attached, making the assemblies large and heavy. In one of the currently available drive systems, the valving is located inside the case and concentric to the input shaft, thus requiring complete removal of the drive system from the vehicle and complete disassembly for servicing. This system is further deficient in that it has a relatively small clutch pack for the transmission brake, with the frictions driven by a clutch hub splined to the output shaft of the system. This arrangement makes the system unable to hold large amounts of engine torque and further requires that the system be quite long and bulky.
The other currently available after-market drive system does not contain a safety sprag clutch, making it possible for the rear tires of a vehicle to lock-up in the event of an engine failure, which could cause the vehicle to crash. The transmission brake is a band surrounding a drum, which is activated by compressed CO2 from an external bottle. Varying CO2 pressures and the requirement of large amounts of CO2 use each time the reverser is shifted via activation of the transmission brake makes this system inconsistent and it requires constant service.
Accordingly, there is a need for a transmission that is small and light in weight while remaining strong and durable, that is readily serviceable with as much service as possible being accomplished without requiring removal from vehicle or substantial disassembly, that contains a safety clutch to provide a disconnect from the engine to the drive wheels in the event of an engine failure, and which is self-contained, requiring no external fluid or gas pressure for operation. The present invention satisfies these needs, as well as others, and generally overcomes the deficiencies found in the background art.
The present invention is an automotive transmission, with an integral anti-lockup assembly included therein, which is compact, light in weight, and which can be quickly and easily disassembled for maintenance and repair. The invention incorporates a racing planetary gear set and shifting mechanism, along with a fluid pump and regulation system, and a transmission brake and safety sprag clutch assembly, inside a single common case which is compact and short in length. The invention is capable of being changed from a two speed transmission to a three or four speed assembly in a manner of minutes by removing the reverser unit and attaching another planetary gear set in it""s own housing and then reinstalling the reverser unit. Shifting of the transmission can be through manual, hydraulic, or pneumatic means.
In its most general terms, the automotive transmission of the invention comprises a single transmission housing or case, an anti-lockup assembly positioned within the transmission case, a planetary gear set assembly positioned within the transmission case and coupled directly to the anti-lockup assembly, a braking assembly positioned to apply braking force directly to the anti-lockup assembly, and a valve assembly located externally from the transmission case. An input assembly is coupled to the anti-lockup assembly proximate to a front end of the transmission case which allows coupling of the transmission of the invention directly to a torque converter. A fluid pump is included in the input assembly.
By way of example, and not necessarily of limitation, the anti-lockup assembly preferably comprises a safety sprag clutch, an inner sprag race, and an outer sprag race, with the sprag clutch positioned between the inner and outer sprag races. The planetary gear set assembly preferably comprises a conventional planetary gear set which couples directly to the outer sprag race.
The brake assembly preferably comprises a transbrake clutch pack and associated piston, with the transbrake clutch pack being structured and configured to frictionally engage or interact with the outer sprag race upon brake activation. The transmission brake clutch pack includes a plurality of alternating friction plates which are splined to the outer diameter of the outer sprag race, and separator plates located and held against rotation by pins in the transmission case.
The input assembly preferably comprises an input shaft, coupled to the inner sprag race, which extends forward from the transmission case to allow coupling to a torque converter. The input assembly further comprises a fluid pump assembly, and front plate associated with the input shaft. The front plate couples to the front of the transmission case to retain the sprag clutch and brake assembly therein. A stator support coupled to the front plate rotationally receives the input shaft, while the fluid pump assembly is mounted on the stator support. The input shaft couples to a torque converter assembly. A housing for the torque converter assembly may be coupled directly to the front end of the transmission case.
The anti-lockup assembly and brake assembly are directly mounted to the front end of the transmission case, while the planetary gear set assembly is mounted directly to the back end of the transmission case. A partition or wall in the case separates the anti-lockup and planetary gear set assemblies. A splined element on the outer sprag clutch engages a corresponding splined input in the planetary gear set proximate to the partition. The splined element, which is physically part of the outer sprag race, transmits rotational energy from the input shaft and sprag clutch assembly to the planetary gear set of the transmission . This arrangement allows the racing transmission of the invention to be more compact and shorter in length than in previously available stand-alone drive units or systems.
The valve assembly preferably comprises a valve body which couples to the bottom of the transmission case. An oil pan also couples to the bottom of the transmission case to cover the valve body and provide an oil reservoir for the valve body. The valve body includes a plurality of oil channels which communicate with inlet and outlet openings in the bottom of the transmission case and with the oil reservoir in the oil pan. A transbrake solenoid in the valve body operates a spool valve in the valve body. The transmission braking provided by the invention is applied by the application of hydraulic pressure behind the piston of the brake assembly, which moves to apply pressure to the transmission brake clutch pack. The hydraulic pressure is controlled by the spool valve and transbrake solenoid, which is remotely actuated by the driver.
It is preferable, but not necessary, to incorporate the safety sprag clutch into the transmission of the invention. The safety sprag clutch allows disengagement of the engine from the transmissions planetary gear set to prevent the lock-up of the rear wheels of the vehicle in the event of an engine failure, and thus is preferred. In embodiments of the invention wherein the sprag clutch is omitted, a brake element structured in the manner of the outer sprag race may be coupled directly to the input shaft, with the transbrake clutch pack acting directly upon the brake element.
A separate reversing planetary gear set assembly is coupled to the planetary gear set proximate the back end of the transmission case to allow for selecting forward, neutral and reverse gears. This reverser assembly is directly mounted to the rear of the transmission case. By removing the reverser assembly, easy access to the planetary gear set for service or the changing of gear ratios is provided. Also, by removing the reverser, additional racing planetary gear assemblies can be mounted to the rear of the transmission of the invention, thereby allowing conversion of the transmission from a standard two-speed unit to one of three, four, or five forward speeds. The reverser is remounted to the final planetary assembly following such conversion.
The positioning of the brake assembly around the outer sprag race, and the coupling of the outer sprag race directly to the planetary gear set, results in a short, compact drive path and correspondingly allows the transmission of the invention to be compact and light weight. The configuration of the transbrake clutch pack around the relatively large surface area provided by the outer sprag clutch additionally provides a larger braking surface area for better braking, and allows transfer of substantial amounts of engine torque. The location of the valve assembly externally from the transmission housing within the oil pan allows quick and easy access to the valves without requiring any disassembly of the transmission itself.
An object of the invention is to provide a racing car transmission apparatus which is compact and light weight.
Another object of the invention is to provide a racing car transmission apparatus which includes a safety sprag clutch assembly to prevent rear wheel lock-up in the event of engine failure, which may lead to a vehicle crash.
Another object of the invention is to provide a racing car transmission apparatus which has externally located valving for easy access without requiring disassembly of the transmission.
Another object of the invention is to provide a racing car transmission apparatus which allows transfer of high levels of engine torque.
Another object of the invention is to provide a racing car transmission apparatus which includes a large transbrake clutch pack for effective braking.
Another object of the invention is to provide a racing car transmission apparatus which eliminates the need for an output shaft between a sprag clutch assembly and a planetary gear set.
Another object of the invention is to provide a racing car transmission apparatus which allows quick and easy detachment and re-attachment of a reverser assembly for conversion of the transmission to different speeds.
Further objects and advantages of the invention will be brought out in the following portions of the specification, wherein the detailed description is for the purpose of fully disclosing the preferred embodiment of the invention without placing limitations thereon.